![]() Viscosity is measured by centipoise (cPs) – essentially this is the thickness of a water-based adhesive. They range from flowing like water up to more viscos options similar to molasses. Water-based adhesives also have different viscosities – defined by application. These require additional effort to mix the adhesive for each application. In some cased, there are two-part systems. This requires some effort to dilute the products to meet the application needs. Water-based adhesives are delivered in bulk containers, such as:ĭepending on the product, there are different concentration levels. Water-based adhesives are also easier to remove from equipment, further minimizing the risk of blockages. Water-based adhesives do not adversely impact rollers and other equipment as they dry. They can be applied via rollers, spray guns, and using immersion processes. High-quality water-based adhesives are extremely quick and easy to apply. Achieving higher solids (26% +) gives better results.Targeting a viscosity between 32–38 seconds.Using fresh adhesive (less than 4 hours after adding resin).When working with additives, manufacturers should consideration the following: In many cases, a dye is incorporated into the formulation to give operators a visual cure the additive was added to the adhesive. These additives crosslink with starch molecules making it more difficult for water to dissolve the mix.Īdhesive with water-resistant additives (WRA) should be used within a certain timeframe after the crosslinking agent is added. These formulations render the formula moisture resistant or waterproof. The most common additive is water resistant resin. Other ingredients are sometimes added include defoamers, biocides, pigments, flame retardants, anti-static, and wetting agents to support different performance needs of the adhesive.Ĭommonly part of water-based adhesive formulations with paper packaging applications, additives play an important role in the various paper application process. Some water-based adhesives contain additives such as surfactants and emulsifiers to stabilize the chemistry. Many natural-based adhesives are perishable and extended storage is not possible. Common applications involve a permeable substrate however, there are other methods involving dry time before the adhesive can be activated with a “quick tack” joining two non-permeable substrates. Adhesive strength results when water evaporates or absorbs into the substrate. Natural-based or bio-based adhesives are supplied in 2 forms – liquid solutions or as dry powders – both are mixed with water prior to application. However, they are susceptible to breakdown when exposed to water. Dextrins are commonly used in the paper industry and very durable with specific materials. Natural-based adhesives with caseins have relatively long drying times, form very strong bonds, and are resistant to water. Some of the most popular are derived from vegetable sources, such as starches and dextrins, or protein sources, such as soybeans, casein, and milk albumen. Natural-based polymers are developed from organic materials. VAEs are also popular in the fabrication of nonwoven products, such as personal hygiene applications. VAEs are widely used in furniture, bookbinding, and textiles applications. Another large category is laminating applications due to their flexibility, moisture resistance, and superior substrate adhesion. VAE adhesives have better flexibility and water resistance with superior bonding properties.įlexible packaging is the biggest application type for VAE adhesives. VAE adhesives offer comparable machining properties to PVAs with improved adhesion to non-porous surfaces. They offer considerable performance advantages over PVA adhesives. The second is Vinyl Acetate Ethylene (VAE) adhesives. Paper applications, such as corrugated board, bookbinding, envelopes and labelling are the most common uses. PVAs are designed for use on porous materials, particularly paper, wood, tissue, nonwovens, cloth, and some stone materials. They are aliphatic, rubbery synthetic polymers and are considered a type of thermoplastic. The first is polyvinyl acetate (PVA) adhesives. There are two primary types of VAM-based emulsions. Česká republika, Čeština (Czech Republic).
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